Generally speaking, mastectomy and lumpectomy plus radiotherapy produce similar outcomes for women with early-stage breast cancer. Both are superior to lumpectomy alone. However, not all women are receiving radiation treatment after lumpectomy. This is true of some lower-income and/or older women who might not be offered radiation or who cannot manage the logistics of weeks of radiotherapy. However, there are also some younger women who are not receiving radiotherapy after lumpectomy because they chose not to undergo it. Now a new study has confirmed that, all too often, young women with breast cancer are not receiving radiation treatment after lumpectomy.
Candidates for breast conserving therapy
Breast conserving therapy, which normally consists of a lumpectomy or partial mastectomy followed by radiotherapy, is an appropriate alternative to mastectomy for the majority early-stage breast cancer patients. Women with relatively small, well-defined tumors are the best candidates. However, radiation treatment is necessary after a lumpectomy to obtain a comparable result to mastectomy.
Having aggressive disease does not necessarily mean that breast conserving treatment is not a good choice. For example, triple negative breast cancer (which is considered aggressive) typically forms a discrete tumor that is relatively easy to visualize radiologically. Therefore, the surgeon can be fairly confident of removing all of the tumor and obtaining clear surgical margins. However, patients with disease that tends to be diffuse (such as lobular or inflammatory breast cancer), multifocal, or difficult to detect have higher rates of mastectomy because initial breast conserving surgery is less likely to result in clear surgical margins.
Radiation treatment after lumpectomy increases survival
Numerous studies have reported that women who undergo radiation treatment after lumpectomy have more favorable survival rates than those who omit radiation. One 2011 meta-analysis of individual patient data for 10,801 women in 17 randomized trials of radiation compared to no radiation reported that radiation treatment halved the rate at which the disease recurred and reduced the breast cancer mortality rate by about a sixth. Factors that reduce the survival benefit of radiation treatment include positive surgical margins and an excessive delay between surgery and radiation.
Surgeons normally attempt to remove a border of normal tissue along with a tumor so that any adjacent abnormal cells that might have migrated from the tumor are removed. Surgical margins are considered to be positive if the pathologist finds cancer cells right up to the edge of the removed tissue. Radiation treatment is designed to eradicate any remaining cancer cells near the tumor or elsewhere in the breast or lymph nodes. Positive margins are associated with reduced survival since radiation treatment cannot be relied upon to eliminate a strip of tumor tissue.
A delay in starting radiotherapy can also reduce survival. In one study of 18,050 women on Medicare at diagnosis, the median time between surgery and the beginning of radiation treatment was 34 days; periods greater than six weeks were found to be associated with a 19% increased risk of local recurrence.
Latest research finds younger women have lowest rates of radiation after lumpectomy
The study referenced at the beginning of this news article was designed to investigate the association of patient age with mastectomy compared to breast conserving surgery, radiation treatment with breast conserving surgery, and radiation after mastectomy. To conduct the study, the authors identified 317,596 women aged 18 to 64 in the National Cancer Database who were diagnosed with invasive breast cancer between 2004 and 2008. A total of 4% of the patients were 35 years or younger and 7% were between 36 and 40 years old. Both of these groups of younger women were more likely to have a mastectomy rather than breast conserving surgery compared to older women. The mastectomy rate was 57% for patients 35 and younger and 52% for those 36 to 40, compared to 35% for those 61 to 64.
Younger women were less likely to receive radiation treatment if breast conserving surgery was performed (69% for age ≤35 and 73% for ages 36-40, compared to 80% for ages 61-64). The overall rates of postmastectomy radiation therapy were low among the women who underwent mastectomy, although younger women were more likely to receive radiation treatment regardless of clinical indications (as would be appropriate). The authors conclude that young women treated with bresat conserving surgery might not be receiving appropriate adjuvant radiation therapy.